Coherent light pulses are employed to perform photo chemistry and also in laser communications systems. In both of these areas, as well as others, short pulses can be advantageous. Over a period of time people have developed systems for generating shorter and shorter pulses. Two papers published by E. Yablonovich [the first with J. Golbhar, Applied Physics Letters, 25, 520 (1970) and the second with H. S. Kwok, Applied Physics Letters, 30, 158 (1977)] disclose a system in which a coherent light pulse is generated by focussing laser light to break down the air through which it travels. The resulting plasma prevents further light from passing through, resulting in a coherent light pulse having a relatively slow rise time, but a fast fall time. This pulse is applied to an absorbing medium which absorbs the coherent light pulse, aligning the molecules in the medium with the field of the coherent light pulse. At the time of the sharp fall time terminating the coherent light pulse, the absorbing medium coherently gives up its stored energy, providing a short pulse having a pulse width related to the line width of the absorbing medium. The amplitude of the short pulse is approximately equal to the amplitude of the initial pulse incident upon the absorbing medium.